Sudden massive slow down when rendering AE composition in PP

Working on a series of very similar videos PP, 9:16 FHD.

With all of them rendering my After Effects compositions (animated titles) runs usually fast.

Except that one Sequence that struggles at a certain point in the timeline and slows down massively almost to a halt from there on. Feels stuck but it is rendering, continental shift slowly, though.

When I de-activate that layer with the AE composition on it, the sequence renders al the lanes and tracks swiftly as always.

Strange thing is: I use the same AE project for ALL those video clips I'm working on at the moment.

I just import different compostions into PP. Each has just a bunch of typewriter-animated titles.

No biggies. And each composition is a copy from one original one, just different wordings. They are almost identical In AE I, can't make out any differences or anomalies at that certain point. Just another title, like all the others.

Only one composition slows that sequence almost to a halt at a precise point when rendering in PP.

All the others render just fine, so no performance or tech issue at all.

I just don't get it...

Thanks to you all for your time.

Falko